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Flexible wearable electronics were developed for applications such as electronic skins, human-machine interactions, healthcare monitoring, and anti-infection therapy. But conventional materials showed impermeability, single sensing ability, and no designated therapy, which hindered their applications. Thus it was still a great challenge to develop electronic devices with multifunctional sensing properties and self-driven anti-infection therapy. Herein, flexible and breathable on-skin electronic devices for multifunctional fabric based sensing and self-driven designated anti-infection therapy were prepared successfully with cellulose nanocrystals/iron(III) ion/polyvinyl alcohol (CNC/Fe3+/PVA) composite. The resultant composite films possessed robust mechanical performances, outstanding conductivity, and distinguished breathability (3.03 kg/(m2·d)), which benefited from the multiple interactions of weak hydrogen bonds and Fe3+ chelation and synergistic effects among CNC, polyaniline (PANI), and PVA. Surprisingly, the film could be assembled as a multifunctional sensor to actively monitor real-time physical and infection related signals such as temperature, moisture, pH, NH3, and human movements even at sweat states. More importantly, this multifunctional device could act as a self-driven therapist to eliminate bacterial by the release of Fe3+, which was driven by the damage of metal coordination Fe-O bonds due to the high temperature caused by infection at wound sites. Thus, the composite films had potential versatile applications in electronic skins, smart wound dressings, human-machine interactions, and self-driven anti-infection therapy.

Polyimides (PIs) and their composites hold promise as low-cost alternatives to conventional ceramic-based dielectrics. Nevertheless, they are far unsatisfactory for practice applications, mainly resulting from the low interfacial compatibility between PI matrices and inorganic fillers. Herein, black phosphorous (BP) nanoflakes/PI composite films with outstanding dielectric and mechanical properties were fabricated via an in situ polymerization pathway. Owing to the hydrophilic surface of BP nanoflakes resulting from slight oxidation during fabrication, the robust noncovalent interaction between BP and PI can be formed, leading to good interfacial compatibility between the two domains and thus well dispersion of BP in PI. Even with a low BP content of 2 wt%, the composite can reach a high-permittivity value of 8.6 at 102 Hz and a low dielectric loss value of 0.02. Moreover, the BP/PI composite films inherited the good mechanical performance of PI matrix due to homogeneous dispersion and low loading of BP.

It is highly desirable yet challenging to develop high-performance microwave absorption materials with lightweight, thin thickness, and strong absorption capability over broad frequency ranges by simple and cost-effective methods. Herein, we design an ultralight (~54 mg cm−3) magnetic-carbon hybrid material to achieve superior microwave absorption performances. By instantaneous freezing-induced self-assembly of Fe3+, Co2+-glucose complexes on a cheap and water-removable template (i.e., NaCl), the as-made composite features 3D hierarchical porous structure and nanosheet-like carbon pore walls embedded with nanocrystalline CoFe2O4. The chemical composition can be controlled by simply altering the ratio of Co2+ (Fe3+) and glucose. Benefitting from the structural and compositional advantages, the optimized composite absorber exhibits a minimum reflection loss value of − 52.29 dB at a thin thickness of 2.0 mm and an effective absorption bandwidth reaching 5.36 GHz (12.64–18 GHz) at a low filler loading of 20 wt%. The microwave absorption mechanism survey reveals that the weak surface reflection and strong dissipation capacity induced by nanosheet-like pore walls combined with the multiple internal reflections caused by 3D hierarchical porous structure contribute to robust impedance matching and strong microwave attenuation ability. This work may offer new insights for designing highly effective magnetic-carbon microwave absorbers with low density and wide absorbing frequency.